Production of solid bio-fuel from cynara. cardunculus (wild artichoke) cultivation

ABSTRACT

The present invention concerns the production of solid biofuel (pellets, briquettes, etc) made from biomass that has, been produced in organized cultivation of the weed  Cynara cardunculus,  and its utilization instead of oil for heat production on a domestic or industrial use or for electricity production. The shifting conventional cropping systems to  cynara  cultivation will multiply the farmers profit and will open new horizons for the development of Greek rural areas also with the respective creation of many new jobs. Additionally, the produced biofuel will be much cheaper than oil or gas for heating, and its use will reduce the dependence from international energy monopolies and the exporting of precious exchange. Apart from the economic advantages, the present invention has direct positive effects on the environment with respect to the greenhouse effect, controlling the pollution with nitrates and agrochemicals, saving large amounts of irrigation water, eliminating soil erosion and land desertification and improving of soil fertility and other chemical and physical characteristics.

The present invention concerns solid biofuel in the form of pellets or briquettes made from biomass which is produced by an organized cultivation of wild artichoke (Cynara cardunculus).

Pellets, briquettes, etc are used as solid fuels in several developed countries already since the last decade. Pellets made from alfalfa and other biomass types are produced also in Greece and particularly on an industrial scale for the production of animal food. In the last 1-2 years, an increased production of pellets made from wastes of the wood-factories (sawdust, scrap and other of wood factories wastes), whereas some agricultural wastes like olive kernel, shells of almonds, nuts, etc, are used as solid fuel for heat production in green houses and other users.

None of the above mentioned cases concern the large scale, organized biomass produced from agricultural cultivation and plant use for solid biofuel (pellets or briquettes) production and the use of this biofuel instead of using oil for heat energy production in Greece and internationally.

The advantages of the invention are many, economic and environmental.

Agricultural economy: According to our calculations, the shifting from traditional cultivations to cynara cardunculus cultivation will multiply the farm profit (ten-fold profit increase with respect to cereals, two-fold increase with respect to cotton cultivation, etc) and will give new perspectives of rural development in Greece and internationally.

National economy: According to our calculations, the selling price of the produced biofuel will be much cheaper per kilogram of oil equivalent (50-70%). Therefore one speaks of the production of Greece and more generally domestic cheap fuel bringing about partial independence of the country from the international oil and natural gas companies and producing countries.

For instance, replacement of 200,000 hectares of wheat (from the total of 1,000,000 ha of cereals or 5% of the total cultivated land in Greece) with Cynara cardunculus, that is possible in the immediate future, would result to the production of 1,000,000 tons oil equivalent for heat generation. Such production is 6.6 times greater than the current obligation of Greece to the European Protocols with respect to bio-fuel production, which is totally imported as yet. Moreover, Cynara cardunculus cultivation for solid biofuel production comprise an important factor of development of the agricultural and national economy with respect to the opening of new markets and the creation of many new working places.

Environment

-   -   Greenhouse effect: As with the use of any kind of biomass         instead of fossil fuels for energy production, the use of Cynara         cardunculus as a solid biofuel decreases the emissions of CO₂ to         values closed to zero, thus greatly contributing to the         controlling of the greenhouse effect.     -   Nitrate pollution: The cultivation of Cynara cardunculus         comprises an important factor against the risk of pollution of         groundwater with nitrates, due to the modest needs of this         cultivation in nitrogen fertilization. As known, nitrate         pollution comprises an important environmental issue in most         lowlands of the country and is connected to the production of         nitrosamines and the formation of cancer.     -   Soil erosion-Desertification: The cultivation of Cynara         cardunculus on slopping lands comprises an important factor         against soil erosion and desertification of the Greek lands,         because this cultivation offers a complete ground cover         throughout the year.     -   Reduction of agro-chemicals: Due to its great compatibility,         Cynara Cardunculus do not allow the mutual growth of other         weeds. The crop is highly tolerant and is not affected by other         diseases or insect attacks. Therefore, the use of fungicides,         pesticides, insecticides, and the rest agrochemicals is almost         zero.     -   Water management: Cynara Cardunculus makes perfect use of the         winter rains and produces high yields without irrigation.     -   Improvement of soil fertility: The contribution of the Cynara         Cardunculus cultivation to the Improvement of soil fertility is         great due to enrichment with organic matter and the creation of         good soil structure, so that high yields of the subsequent crops         are expected.

Cynara Cardunculus (in English Cardoon, or Spanish thistle artichoke or Wild artichoke or Cynara) is a perennial crop (1) of Mediterranean origin, well adapted to the xerothermic conditions of southern Europe. Cardoon's growth starts after the first rains in autumn and continues during winter and spring until the beginning of summer, when soil moisture drops at very low levels and the aerial part of the plant dries out. Then the crop can be harvested in the period June-August (2). With the onset of the first rains in October, fast re-growth takes place and the crop canopy will fully cover the soil within few days, and so forth. Due to the fact that Cynara Cardunculus is itself a tough weed (invader), it would not let the growth of the weeds, whereas in many year field experiments this crop was not affected by pest and diseases, so that the cultivation can be successful without the use of agro-chemicals. Additionally, due to its rich and deep root system, Cynara Cardunculus take perfect advantage of the soil fertility and does not need but zero to minimum amounts of nitrogen fertilization. In earlier experiments of the candidate for the patent, quite high yields were harvested under zero fertilization until the third year of cultivation, and with up to 50 kg N/ha after the forth year. Cynara Cardunculus takes perfect advantage of the winter rains and performs high biomass yields without irrigation. The dry biomass yield ranges from 12 to 16 t/ha without irrigation, whereas if 2-3 irrigation applications take place from mid-April to the end of May (in this particular period water is readily available in most areas), yields of 20 to over 25 t/ha are normally expected. It should be noticed that in contrast to other cultivations, the cost of cultivating Cynara Cardunculus is very small.

On the other hand, Cynara Cardunculus pellets (5) are small, cylindrical pieces of compressed biomass from this crop with various sizes (i.e. diameter 6 mm, length 30 mm, etc) that can be easily packed, transported with trucks (6) and stored in storage rooms, from where they can transferred and feed automatically modern furnishes and ovens with an controlled and adjustable flow rate. Pellets have a moisture content of about 8% (bulk weight about 650 kg per cubic meter) and heat value of 16-18 MJ/kg, or in other words, 2 kilograms of cynara pellet correspond with 1 liter of oil. The ash content is about 5-7% and can be considered insignificant in modern furnishes, whereas on the other hand the ash itself can comprise a significant source of inorganic fertilizer.

For the establishment of Cynara cardunculus, the existing equipment can be utilized. Field preparation is needed by means of plowing and 2-3 harrowings. The cost of field preparation is estimated at 160-190

/ha if labor is hired (man-and-machine), whereas if own equipment is used, the field preparation cost remains lower than 50

/ha. Field preparation is followed by sowing that can be realized with normal pneumatic sowing machines. Cynara seed is available today against 15

/kg, whereas 10 kg of seed are required for sowing 40-50 hectares. Thus, the total cost of sowing (including labor cost) is estimated at 70-80

/ha. Based on the above, the cost of establishment of Cynara cardunculus cultivation will range from 120 to 270

/ha, and considering a life period of 10 years, the annual cost of establishment will range from 12 to 27

/ha, that is practically negligible. After crop establishment, the harvest of cynara's biomass once in a year comprises the only intervention in the field, apart from the cases of unfertile soils that light nitrogen fertilization (0-50 kg N/ha) will be needed after the third or fourth year of growth.

Harvesting of the cynara crop can be realized using the existing equipment foe harvesting and collecting biomass in balls, small (3) or large ones. These balls will be transported with trucks or platforms to the process plant. The candidate for the patent has calculated that the total cost of harvest, transportation of biomass to the door of the plant is 20-30

/t using the existing equipment, whereas by using modern harvesting and balling machines, this cost will be reduced at 10-20

/t.

In the plant, biomass will be smashed and fragmented with a hammer (4) and will be pelletized to produce the final product that is pellets or briquettes of Cynara Cardunculus (5). This product has a great heat value, good combustion characteristics and very low sulfur concentration. The heat value of the product is 17-19 MJ/kg (moisture content at harvest 10%), or in other words about the half of the heating value of oil (41-42 MJ/kg). Solid biofuel in the form of pellets is used presently in the markets of Italy, Germany, The Netherlands, and other countries of the E.U. The present price in the Italian market is 180

/t (large quantities) to more than 240

/t in small 15-kg bugs. It is believed that soon pellets for heating will be available in the Greek market as well. The first ovens and furnishes for domestic (8) and industrial (7) use have been already imported in the Greek market. The capacity of a pelletizing plant of medium capacity is about 50,000 t annually (experiment with industrial production of 7 t cynara pellets per hour in Palamas, Karditsa, times 7000 hours of operation annually). The cost of establishment of such a plant is about 1.5 million

, whereas according to our calculations the annual operation and depreciation cost will remain below 20

/t (i.e. 1,000,000

concerning mainly the cost of electricity, labor, materials, maintainance and other expenses). It is of paramount importance to stress that the harvested biomass contains about 15% seed with oil content 25%. Thus the oil content in biomass is 3.75% and this is proved perfect for greatly increasing the production rate of the product (pellets) actually by 7-15 times comparing to the palletizing other wood materials or crop remnants (straw, scrap, etc). This may reduce the operation cost up to ten fold, e.g. from 100 to only 10

/t.

The first experimental production of Cynara cardunculus pellets on an industrial basis has taken place in Greece on Nov. 10, 2006 (1-5) under the coordination of the candidate for the patent in cooperation with well-known industry of animal food production, located in Palamas, Karditsa, central Greece. This event enjoyed great publicity in the local and national press and television.

Although the economic pie will be determined by the market, it is easily understandable that the selling price of cynara biomass by the farmer will be at least 60

/t. To this conclusion agree the first two factory owners in Greece, located in Karditsa (Palamas) and Larissa (Sykourio). This means that, according to our estimations, the profit of the farmer will be in the range of 720-900

/ha for biomass yields in the order of 12 -15 t dry biomass per ha (versus profit of about 100

/ha in the case of wheat cultivation today). In the case of irrigated fields (for instance replacement of cotton cultivation), the profit of the farmer will raise at 2000

/ha (versus 1200

/ha in the case of cotton) taking in to account the irrigation cost as well. To the above prices the subsidies are excluded (farmer check, organic farming, nitrate pollution subsidy, etc), neither the subsidy of 45

/ha attributed to the energy crops!

It is easy to understand what means to produce your own fuel or at least a part of it. Decrease of the dependence from international monopolies of energy, saving of precious exchange, etc. For instance, replacement of 200,000 ha of wheat (out of 1,000,000 ha of cereals or 5% of the total agricultural land) with Cynara cardunculus, which is considered to be possible in the immediate future, would bring about a production of 1.000.000 t oil equivalent. This production is currently 6.6 times greater than the present obligation of Greece for the production of bio-fuel (which is presently totally imported), resulting in an enormous benefit to the Greek consumer, which according to our estimations may surpass the one/third of the oil price.

Finally, we should mention the thousand new jobs which will be created for the harvest, transportation, process and marketing of the new product. 

1-6. (canceled)
 7. A solid bio-fuel comprising: dry processed biomass from Cynara cardunculus (wild artichoke) cultivation, said biomass having a heating value of at least 16 MJ/kg.
 8. The solid bio-fuel according to claim 7, wherein said processed biomass includes seeds of said Cynara cardunculus cultivation.
 9. The solid bio-fuel according to claim 7, wherein said processed biomass is in the form of at least one pellet.
 10. The solid bio-fuel according to claim 9, wherein said pellet has a length longer than its diameter.
 11. The solid bio-fuel according to claim 9, wherein said pellet has a substantially circular cross section less than about 1.2 cm in diameter.
 12. The solid bio-fuel according to claim 9, wherein any cross section of said pellet is less than about 5 cm in length.
 13. The solid bio-fuel according to claim 9, wherein said pellet is configured for use in residential pellet equipment selected from the group consisting of a stove, an oven, a burner, a greater furnace, and a blast furnace.
 14. The solid bio-fuel according to claim 9, wherein said pellet has a moisture content of about 8%.
 15. The solid bio-fuel according to claim 7, wherein said processed biomass is in the form of at least one briquette.
 16. The solid bio-fuel according to claim 15, wherein said briquette has a length longer than its diameter.
 17. The solid bio-fuel according to claim 15, wherein said briquette has a substantially circular cross section less than about 10 cm in diameter.
 18. The solid bio-fuel according to claim 15, wherein any cross section of said briquette is less than about 25 cm in length.
 19. The solid bio-fuel according to claim 15, wherein said briquette is configured for use in residential briquette equipment selected from the group consisting of a stove, an oven, a burner, a greater furnace, and a blast furnace.
 20. A method of producing a solid bio-fuel from Cynara cardunculus, said method comprising the steps of: (a) harvesting a crop of Cynara cardunculus (wild artichoke) cultivation; (b) collecting biomass from said harvested crop; (c) smashing and fragmenting said biomass; and (d) forming said smashed and fragmented biomass into a pelletized product having a heating value of at least 16 MJ/kg.
 21. The method according to claim 20, wherein step (b) further comprising the step of producing biomass balls from said collected biomass.
 22. The method according to claim 21, wherein step (c) uses at least one hammer to smash and fragment said biomass balls.
 23. The method according to claim 22, wherein said pelletized product of step (d) is at least one pellet having a length longer than its diameter, a substantially circular cross section less than about 1.2 cm in diameter, and any cross section of said pellet is less than about 5 cm in length.
 24. The method according to claim 23, wherein said pellet has a moisture content of about 8%.
 25. The method according to claim 22, wherein said pelletized product of step (d) is at least one briquette having a length longer than its diameter, a substantially circular cross section less than about 10 cm in diameter, and any cross section of said pellet is less than about 25 cm in length.
 26. The method according to claim 20, wherein said crop of Cynara cardunculus in step (a) has a moisture content of about 10%. 